IfcSectionedSolidHorizontal

Item	SPF	XML	Change	Description
IFC4x1 Final 4.1.0.0
IfcSectionedSolidHorizontal			ADDED
IFC4x3_RC1 to IFC4x3_RC2
IfcSectionedSolidHorizontal
CrossSectionPositions	X	X	MODIFIED	Type changed from IfcDistanceExpression to IfcPointByDistanceExpression.
IFC4x3_RC2 to IFC4x3_RC3
IfcSectionedSolidHorizontal
CrossSectionPositions	X	X	MODIFIED	Type changed from IfcPointByDistanceExpression to IfcCurveMeasureSelect.
IFC4x3_RC4 Update
IfcSectionedSolidHorizontal
FixedAxisVertical	X		DELETED

Semantic definitions at the entity

Entity definition

An IfcSectionedSolidHorizontal is a solid model constructed by sweeping potentially varying cross sections along a curve horizontally.

The solid is generated by sweeping the CrossSections between CrossSectionPositions with linear interpolation between profile points with the same tag along the directrix. The profile normal is derived from the associated IfcAxis2PlacementLinear, not necessarily the tangent of the Directrix. The profile X axis is the direction of RefDirection from IfcAxis2PlacementLinear, and the profile Y axis is the direction of Axis.

For sections having cross-section rotated according to a single super-elevation, IfcDerivedProfileDef may be used to indicate such rotation with each ParentProfile referring to the same underlying profile. For sections having cross-section transformed according to multiple super-elevations with points varying independently, each profile may be of a different instance but of same type (e.g. IfcArbitraryClosedProfileDef), and may optionally have cross section points associated to string lines ("guide curves") by matching labels using IfcIndexedPolyCurve with IfcCartesianPointList2D.TagList.

Figure 497 illustrates four girders of a bridge having a constant parameterized profile, two guardrails having a constant arbitrary profile (one of them mirrored), and a bridge deck having a variable arbitrary profile.

Figure 497 — Sectioned solid horizontal

Informal Propositions:

No two consecutive sections shall intersect.
If the type of sections is not IfcParameterizedProfileDef (i.e. an arbitrary profile), then the number of points and edges should be the same for two consecutive profiles
If the directrix is not tangent continuous, the resulting solid is created by a miter at half angle between the two segments.
Very sharp edges may result in nearly impossible miter; implementer agreements may define acceptable limits for tangent discontinuity or require the directrix to be tangent continuous.
The directrix shall not intersect

Attribute definitions

#	Attribute	Type	Cardinality	Description	G
3	CrossSectionPositions	IfcAxis2PlacementLinear	L[2:?]	Position coordinate systems in sequentially increasing order paired with CrossSections, indicating the position of the corresponding section along the Directrix.	X

Formal Propositions

Rule	Description
CorrespondingSectionPositions	The set of cross sections and the set of cross section positions shall be of the same size.
NoLongitudinalOffsets	Distance expressions must not use longitudinal offsets.

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	G
IfcRepresentationItem
	LayerAssignment	IfcPresentationLayerAssignment @AssignedItems	S[0:1]	Assignment of the representation item to a single or multiple layer(s). The LayerAssignments can override a LayerAssignments of the IfcRepresentation it is used within the list of Items. IFC2x3 CHANGE The inverse attribute LayerAssignments has been added. IFC4 CHANGE The inverse attribute LayerAssignment has been restricted to max 1. Upward compatibility for file based exchange is guaranteed.	X
	StyledByItem	IfcStyledItem @Item	S[0:1]	Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve. IFC2x3 CHANGE The inverse attribute StyledByItem has been added.	X
IfcGeometricRepresentationItem
IfcSolidModel
	Dim :=3	IfcDimensionCount		The space dimensionality of this class, it is always 3.	X
IfcSectionedSolid
1	Directrix	IfcCurve		The curve used to define the sweeping operation.	X
2	CrossSections	IfcProfileDef	L[2:?]	List of cross sections in sequential order along the Directrix.	X
IfcSectionedSolidHorizontal
3	CrossSectionPositions	IfcAxis2PlacementLinear	L[2:?]	Position coordinate systems in sequentially increasing order paired with CrossSections, indicating the position of the corresponding section along the Directrix.	X

Formal representations

XML Specification

 <xs:element name="IfcSectionedSolidHorizontal" type="ifc:IfcSectionedSolidHorizontal" substitutionGroup="ifc:IfcSectionedSolid" nillable="true"/>

 <xs:complexType name="IfcSectionedSolidHorizontal">

  <xs:complexContent>

   <xs:extension base="ifc:IfcSectionedSolid">

    <xs:sequence>

     <xs:element name="CrossSectionPositions">

      <xs:complexType>

       <xs:sequence>

        <xs:element ref="ifc:IfcAxis2PlacementLinear" minOccurs="2" maxOccurs="unbounded"/>

       </xs:sequence>

       <xs:attribute ref="ifc:itemType" fixed="ifc:IfcAxis2PlacementLinear"/>

       <xs:attribute ref="ifc:cType" fixed="list"/>

       <xs:attribute ref="ifc:arraySize" use="optional"/>

      </xs:complexType>

     </xs:element>

    </xs:sequence>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcSectionedSolidHorizontal

 SUBTYPE OF (IfcSectionedSolid);

  CrossSectionPositions : LIST [2:?] OF IfcAxis2PlacementLinear;

 WHERE

  CorrespondingSectionPositions : SIZEOF(CrossSections) = SIZEOF(CrossSectionPositions);
  NoLongitudinalOffsets : SIZEOF(QUERY(temp <* CrossSectionPositions | EXISTS(temp.Location.OffsetLongitudinal))) = 0;
END_ENTITY;

 EXPRESS-G diagram